1. Field of the Invention
This invention generally relates to detection of viral infection and, in particular, to apparatus and methods for high-throughput, reproducible and inexpensive detection of virus infection using multiplexing technologies.
2. Background of the Technology
Virus infection can be detected with a number of conventional approaches, such as Enzyme-Linked Immunosorbent Assay (ELISA), Enzyme-linked immunoassay (EIA), and Western bolt, which typically detect the presence of a viral antigen or an antibody to a viral antigen. The limitations of conventional assays include low throughput, low automation, consumption of large amount of samples and reagents, and high assay cost. For example, a commonly used method for monitoring virus infections in laboratory mice and rats is an ELISA for detecting antivirus antibodies in the serum of the animal. The assay method, however, is time consuming and is capable of measuring only one antibody level per assay.
In recent years, multiplexed assays are gradually becoming a prevailing technology in the field of immunoassays, especially in the pharmacogenomics arena for drug discovery and clinical diagnostics purposes. The multiplexed assays allow simultaneous detection or quantification of multiple analytes from a single sample. One of the approaches to performing multiplexed assays is microarray, which was originally developed as a DNA/RNA based array system but has since evolved to include other array systems such as protein microarrays. Protein microarrays are compatible with hardware and software used by the DNA microarrays. Since protein microarrays facilitate the analysis of protein-protein, protein-ligand or protein-drug interactions, as well as enzymatic assays, they have been used in basic research and development, drug target identification and validation, drug screening, toxicity screening, lead optimization, and patient stratification for clinical trials and disease management (See, for example, Bussow. et al., Nucleic Acids Res, 26:5007-5008, 1998; Eisen et al., Methods Enzymol. 303:179-2000, 1999; Knezevic, et al., Proteomics, 1:1271-1278, 2001; Adam et al., Proteomics, 1:1264-1270, 2001; Zhu, et al., Current Opinion in Chemical Biology, 5:40-45, 2001; and Ronald et al., Proteome Research, 1:233-237, 2002).
In addition to various protein microarrays, other multiplexed analysis approaches of proteins include bead-based technology, which performs discrete bioassays of multiple proteins on the surface of fluorescent color-coded or differently sized beads known as microspheres. During the bioassays, those beads are read in a compact analyzer/flow cytometer, which simultaneously identifies the bioassays and measures the results, all in real time when sample is directly labeled with fluorophores.
While the multiplexed assay technologies, such as the micro arrays and beads technology, have been employed in many research and clinical applications, they have not been used for the monitoring viral infections in animals.